Method
Clean and cut the rhubarb and let it rest with 3 tbs sugar.
Preheat the oven to 200 ° C and line a baking sheet (approx. 30 cm by 35 cm) with baking paper.
Beat the butter until foamy, add sugar and vanilla sugar, then stir in the eggs one at a time. Stir in the lemon zest, salt, and buttermilk. Mix the flour with the baking powder and ground almonds in a second bowl and add to the rest of the ingredients.
Fill the dough into the baking sheet. Top with the rhubarb, arrange 2 horizontally, 2 vertically on the dough, and press down a little.
Mix together all the ingredients for the cake crumble and then crumble over the rhubarb. Bake in the preheated oven for approx. 25-30 minutes until golden.
